Central valve for a camshaft adjustment device

Abstract

A central valve for a camshaft adjuster, and to an internal combustion engine, which includes a camshaft, a camshaft-adjusting device, and a central valve. The central valve includes a shaped part as a valve housing ( 3 ), including a control piston ( 4 ) guided coaxially within the valve housing ( 3 ) in such a way that the control piston can move axially and including a stop, which limits the mobility of the control piston in an axial direction (piston stop). The piston stop is a piston stop washer ( 5 ), wherein the piston stop washer and the valve housing ( 3 ) are joined.

What is claimed is: 
     
       1. A central valve for a camshaft adjustment device, the central valve comprising:
 a shaped part valve housing; 
 a control piston coaxially and axially movably guided within the valve housing; and 
 a piston stop that limits a movability of the control piston in an axial direction, the piston stop being a piston stop washer, the piston stop washer and the valve housing being joined, 
 the valve housing having at least one notch in a stop area of the piston stop washer, the piston stop washer having at least one radial expansion adapted to the at least one notch, the piston stop washer and the valve housing via of the at least one radial expansion being permanently non-detachably joined in a notch area of the at least one notch, the piston stop washer in a radial expansion area of the at least one radial expansion having a larger radius than the valve housing, 
 wherein the at least one radial expansion includes a first radial expansion and a second radial expansion, the first radial expansion extending further radially outward from a center of the piston stop washer than the second radial expansion. 
 
     
     
       2. The central valve as recited in  claim 1  wherein the piston stop washer at the larger radius defines an overhang. 
     
     
       3. The central valve as recited in  claim 1  wherein the control piston at a first end is acted on by force of a spring, and at a second end has an actuating surface on an end-face side, the piston stop washer being situated at the second end having a recess. 
     
     
       4. The central valve as recited in  claim 1  wherein the valve housing is a deep-drawn part. 
     
     
       5. The central valve as recited in  claim 1  wherein the at least one notch includes two notches in the stop area of the piston stop washer, the at least one radial expansion including two radial expansions adapted to the two notches, the piston stop washer and the valve housing being caulked via the two radial expansions in an area of the two notches. 
     
     
       6. The central valve as recited in  claim 1  wherein the piston stop washer is a continuous ring. 
     
     
       7. The central valve as recited in  claim 1  wherein an inner circumferential surface of the piston stop washer has a uniform diameter. 
     
     
       8. An internal combustion engine comprising:
 a camshaft; 
 a camshaft adjustment device; and 
 a central valve for the camshaft adjustment device, the central valve comprising:
 a shaped part valve housing; 
 a control piston coaxially and axially movably guided within the valve housing; and 
 a piston stop that limits a movability of the control piston in an axial direction, the piston stop being a piston stop washer, the piston stop washer and the valve housing being joined, 
 the valve housing having at least one notch in a stop area of the piston stop washer, the piston stop washer having at least one radial expansion adapted to the at least one notch, the piston stop washer and the valve housing with an aid via of the at least one radial expansion being permanently non-detachably joined in a notch area of the at least one notch, the piston stop washer in a radial expansion area of the at least one radial expansion having a larger radius than the valve housing, 
 wherein the at least one radial expansion includes a first radial expansion and a second radial expansion, the first radial expansion extending further radially outward from a center of the piston stop washer than the second radial expansion, 
 
 the valve housing being concentrically situated in a borehole of the camshaft, and the valve housing having a radial passage, as a supply connection, axially situated in a passage area of a corresponding radial passage in the camshaft. 
 
     
     
       9. The internal combustion engine as recited in  claim 8  wherein the valve housing has a circumferential groove on an outer surface of the valve housing in a passage area of the corresponding radial passage. 
     
     
       10. The internal combustion engine as recited in  claim 8  wherein the piston stop washer at the larger radius defines an overhang and wherein the valve housing is enclosed by the borehole of the camshaft, the camshaft having a stop surface, the valve housing being supported via of the overhang against the stop surface. 
     
     
       11. The internal combustion engine as recited in  claim 10  wherein the stop surface and the overhang cooperate in such a way that a movability of the valve housing is limited axially in a direction of a first end of the control piston, or is limited axially in the direction of the first end and in a circumferential direction, a locking ring being situated on an inner circumferential surface of the borehole of the camshaft limiting the movability of the valve housing axially in a direction of a second end of the control piston. 
     
     
       12. A central valve for a camshaft adjustment device, the central valve comprising:
 a shaped part valve housing; 
 a control piston coaxially and axially movably guided within the valve housing; and 
 a piston stop that limits a movability of the control piston in an axial direction, the piston stop being a piston stop washer, the piston stop washer and the valve housing being joined, 
 the valve housing having at least one notch in a stop area of the piston stop washer, the piston stop washer having at least one radial expansion adapted to the at least one notch, the piston stop washer and the valve housing via of the at least one radial expansion being permanently non-detachably joined in a notch area of the at least one notch, the piston stop washer in a radial expansion area of the at least one radial expansion having a larger radius than the valve housing, 
 wherein the piston stop washer has at least one arcuate outer circumferential surface section past which the at least one radial expansion protrudes radially, the at least one arcuate outer circumferential surface section being circumferentially wider than the at least one radial expansion.